New imaging methods are being developed at a rapid pace. To validate and characterize these new imaging methods, comparisons with 'gold standards'or ground-truth must be performed. Histology is generally considered to be the ground-truth, from which clinical decisions are derived. However, in processing tissues for histology, the samples are often torn and distorted due to shrinking. These deformations are often inhomogeneous, e.g., the tumor may shrink more than the adjacent muscle. Image registration techniques used to validate new imaging modalities with histology are frustrated by the fact that the in vivo image needs to be warped to match the ground-truth histology. The overall goal of this project is to provide a means to identify image based biomarker surrogates for cancer treatment. We have preserved samples from an ongoing study where we are using MRI to try to identify a signature for a response to a novel antivascular therapy. However, we do not have an efficient and robust histological registration method for that study. Therefore we shall develop an accurate registration method that can be used to correlate pixels in a histology slide with voxels in the registered, in vivo, 3D tomographic image, e.g., MRI, CT, etc. We propose to develop a cast immobilization system that facilitates image registration and aligning of the histological slices into a 3D volume. The cast also will improve the tomographic image quality by suppressing motion artifacts. Software will be developed to register the 3D histological volume with MRI (for example), using both outside boundaries and internal landmarks. We shall then characterize the accuracy of the histology registration system and finally apply the method to a set of samples from a collaborative project which uses MRI to assess the effects of an antivascular treatment. The proposal requests support for the development of a critical component in the validation of new imaging modalities and the discovery of new non-invasive biomarkers. The work proposed here will develop an important tool that will be critical for a large number of pre-clinical research projects at the University of Chicago and collaborating institutions. In addition, later extensions of the method proposed here will support clinical research by allowing registration of images of patients with biopsy and lumpectomy samples. PUBLIC HEALTH RELEVANCE: The proposed multimodality imaging and histology registration system will be an important technology for validating new imaging techniques and will greatly enhance ongoing research projects at the University of Chicago as well as other institutions. Histology is the accepted standard used to validate diagnoses. The ability to compare non-invasive imaging to histology, accurately and quantitatively, will further the discovery of biomarker surrogates.